Graphitic bearing



ll atentet'l drum 2%,

enariarric nnaarne.

in namin The object of my invention is to provide graphitic bearing oirelatively great strength combined With a much lower trictioncoefficient than has heretofore been characteristic of reasonably stronggraphitic bearings. My improved bearing is of special value t'or thrustbearings, which may be in ring form or other suitable form. T havediscovered that a mechanically strong graphitic bearing of low frictioncoeli -icient can be produced in the following Way:

it take mined graphite ore which isamorphous and Which also contains acertain percentages of ash to give strength, but it is important thatthis ash content shall also be amorphous. The amount of amorphous ashmay be in the neighbourhood of 10 per cent or over. y For example I haveused with success, an amorphous graphitic ore analyzing something over82 per cent graphitic carbon, with about eight per cent silica and about4 percent alumina, and small percentages or traces of other matters,such as moisture, volatile matter, calcium oxide, etc.

This amorphous graphitic ore, finely pulverized is thoroughly mixed Withequally finely pulverized petroleum coke and then a bonding agent, suchas crushed coal tar pitch added. Thereupon to the mixture there is addeda solvent for the pitch. This solvent may be benzol or na htha or othersuch coal-tar derivative, su cient of this solvent being used todissolve the pitch and make a homogeneousmixture in the form of aplastic mass when stirred in a mixer.

The product is then dried and re-pulverized, after which the powderymixture may be pressed into the desired shape, as by a hydraulic pressunder a pressure of from live to twenty tons per square inch.

Application filed February l, 1924. Serial No. 690,0348.

The pressed pieces are baked at a temperature which may range from about750 C. to 1500 0., and are then ready for use, and as l have said, lhave found these bearings strong and lubricative Without abrasion.

The proportions of the coke, graphite and pitch may be in threesubstantially equal parts, although ll preterto use a larger percentageof coke and a smaller percentage of the bonding agent.

The term amorphous graphite"? is used in this specification to designatethose finely divided graphite ores which exhibit no semblance ofcrystalline structure. The ash in such ores isequally finely divided,but

by the term amorphous ash ll do not Wish to exclude the possibility thatsuch ash or some of it may tend to recrystallize under ,the heattreatment Thave described.

I claim as my invention: 1. A. graphitic bearing, consisting of. a bakedmixture of petroleum coke and graph ite and, a coal tar derivative, thegraphite belng amorphous and containing a substantial per cent ofamorphous ash.

2. The method of producing a graphitic product which comprisesintimately commingling finely divided graphite and petroleumcokewithcoal tar in the presence of a volatile solvent for the latter, toform a pastein which the graphite, coke and tar are present insubstantially equal proportions, but the coke somewhat predominatingover the tar, drying the mixture, pulverizing the dried mass, subjectingthe dried, pulverized mass to heavy pressure, and baking the latter at atemperature of at least 7 C.

lln testimony whereof T have signed my name to this specification.

CHAS. W. ADAMS.

